Making money appears to be John Duffield's main motivation in life. For his secretaries and star fund managers, the maverick entrepreneur is able to claim that he knows how to create wealth. At least 250 people have experienced his Midas touch.

Until now, perhaps. Slightly scruffy in M&S V-neck sweaters and cord trousers, Duffield's illustrious City career hit the rocks this week when the banks seized control of his high-profile New Star fund management operation.

Shareholders in New Star have been all but wiped out in a sign of how the credit crunch is touching every sector of finance. By last night shares in the fund manager had almost reached the "token 1p" that Altium stockbrokers rated them earlier in the week - a painful slide from a high of £4.85 barely 18 months ago.

Duffield had been reluctant to concede control of New Star to a group of banks, which could end up with a 95% stake in the operation he founded amid much controversy seven years ago. An impatient man who does not suffer fools lightly, he is unlikely to have found negotiating with the bankers easy. At times it was far from certain that a deal would be struck. But Duffield, who made more than £150m from New Star - with many of his 300 or so staff also becoming multimillionaires - finally caved in on Wednesday.

When the announcement was made, after 72 hours of dire trading in New Star shares, Duffield still had a role in a company over which the taxpayer will have an influence - as the syndicate of banks includes those being bailed out by the government: HBOS, Lloyds TSB and Royal Bank of Scotland.

But Duffield is not expected to stay long beyond the radical restructuring, which is due to be completed early in the new year. The banks will want new leadership and Duffield seems unlikely to want to stay - although one of his favoured analogies is of an aeroplane crashing to the ground: do you kick out the pilot, and if so, when?

Short temper

His experience of running firms when he is not the master has not been successful, but helped to create the legend that surrounds this short-tempered and slightly ill-mannered man. When he sold his Jupiter fund management operation to Commerzbank, he had a very public falling-out after describing three executives of the German bank as Goering, Goebbels and Hitler.

He later said he did it with a "smile on my face". The joke was obviously lost on the Germans but did not stop Duffield's rise. He went on to set up New Star - an obvious play on Jupiter - taking many colleagues with him but leaving behind Edward Bonham Carter, who still runs the operation. All this came with another high-profile spat that almost ended up in the courts.

New Star had been a raging success. It hauled in billions of pounds from small investors attracted by the company's galaxy of star fund managers, whose names were displayed on advertising billboards that Duffield made his senior staff check personally to ensure they were lit correctly and clearly displayed.

His "stars" were sometimes trusted with his own money and motivated not by their salaries but by the lure of potentially lucrative share stakes. Staff owned about 50% of New Star when it floated three years ago, although that stake has halved since they started to sell out last year.

The precipitous decline in the share price makes it harder to keep them motivated - hence the £10m of shares that the banks have agreed can be used to tie in staff.

A collapsing share price also does little to instil confidence among the investors in New Star's funds, which have plummeted down performance tables. Investors have begun to withdraw their savings from the group's unit trusts and investment funds. At its height New Star had £20bn under management, but this week admitted this had fallen to just under £15bn. Last week, New Star temporarily closed the doors on its international property fund to stem the exodus.

At the core of New Star's problems was debt: some £240m was borrowed in March 2007, before the credit crunch began, to allow the group to return £383m to shareholders, who were mainly Duffield and his staff. Duffield is not a high spender and has given £12m to charity in recent years. His main indulgence is in the farms he owns in Newbury and Oxford.

New Star admitted that amid all the turmoil, investors had been expressing concern about the debt burden, which required millions of pounds a year to service at a time when profits were being hit by the deepening malaise.

From the moment that New Star admitted in an announcement to the stock exchange early on Monday morning that it was asking for trading in its shares to be suspended while negotiating with its bankers, the outcome looked painful for Duffield. The authorities rejected the request to suspend trading - in a rare public disagreement between a company and the Financial Services Authority - and the shares dived 70%.

Duffield has been reluctant to speak openly about the events of the past week but appeared unrepentant in a statement. "The cost of this restructuring is regrettably a substantial dilution for ordinary shareholders, including me. However, in current market conditions we have to recognise that there is no other option to ensure the stability of the business," he said.

Well-connected

Quite what the future holds for the well-connected Duffield is uncertain. Richard Pease, of the Barclays banking clan, is on the New Star board and one of the top fund managers; the former FSA chief executive John Tiner is a non-executive director; Martin Gilbert, who runs the rival Aberdeen Asset Management, is a friend.

With his 70th birthday looming in June, he could easily settle for retirement, but friends say the prospect of relaxation will not come easily to him. Although he has an unusually leisurely start for the City - at about 11am - he puts in 12-hour days, usually involving lunch and dinner in Signor Sassi, the Italian restaurant he frequents near his Knightsbridge office.

He tried retirement before: at the age of 30, he lived the high life with his heiress wife Vivien Clore. It did not last and neither did the marriage - they divorced after seven years but not before having two children, Arabella and George.

Clore, a philanthropist, is said to have described him as a wonderful fund manager but a lousy husband. Only she can confirm his credentials as a husband but the reality is that he does not manage money directly. He describes himself as "manager of mangers" and has said that "you don't need colossal brains to succeed in this business but you need common sense - and you must work hard."

Educated at Harrow, then Oxford, where he obtained a first in biochemistry, Duffield's few interests outside work appear to be his farms and his children. Friends say he showed little appetite for taking a back seat even as the credit crunch started to hurt his business.

But whether he has the appetite to start another venture from scratch in what is expected to be the worst economic climate since the Great Depression remains to be seen. But, Duffield being Duffield, anything is possible.

John Duffield

Born 1939

Education Harrow school and Christ Church, Oxford, where he read biochemistry